What is the dispute about?

The Unite union has called the strike in protest at plans by Grangemouth owner Ineos to close its final salary pension scheme to new workers. Workers are also concerned that the company wants to introduce new working practices. Ineos inherited the pension scheme when it bought the Grangemouth plant from BP in 2005.

What is the union's argument?

Unite claims there are no grounds for closing the scheme, which it says is in surplus and requires only £16m a year funding by the company; meanwhile, Grangemouth makes up to £3m a day in profits. The changes being proposed by Ineos would reduce workers' payouts by an average of £10,000 a year, Unite says. It claims workers at Grangemouth are paid about £6,000 less than workers at other refineries.

What does Ineos say?

That it will still provide generous pensions for its employees and that a quarter of the entire salary bill at Grangemouth is already going into the pension fund. It says the final salary arrangement will remain for existing workers, but the main difference will be that staff will have to make a contribution for the first time, bringing them into line with the vast majority of workers elsewhere in the UK. It says it cannot afford to fund the scheme to new workers and that investment in the plant will be threatened if future strikes go ahead.

Why is the dispute important?

About 10 per cent of the UK's petrol is refined at Grangemouth. Shutting it down for a long period of time could have an impact on fuel supplies and result in price hikes. It also supplies power and steam to a nearby BP plant, which is connected to the main pipeline bringing in oil and gas from the North Sea.

Could we see oil and gas price hikes?

In the short term this is highly unlikely. There is plenty of fuel coming in from other sources. However, prolonged industrial action could have a knock-on effect and see prices rise.

What are the prospects of more talks?

Two days of talks at the London headquarters of the conciliation service Acas collapsed last week and there are no plans for an early resumption of negotiations. Informal talks were continuing yesterday, but both sides seem unwilling to give way on any substantive issues.